Rotary motors, pumps and compressors have been known for many years. Generally these devices consist of a housing or casing within which one or more vanes rotate. This is in contrast to those devices that utilize a reciprocating, linearly moving piston. In the case of rotary pumps or compressors, the vanes are rotated by a shaft to pressurize or cause the fluid to flow through the device. In the case of a rotary motor, the opposite occurs. Fluid is introduced into the device under pressure to displace the vanes, which in turn rotate and power a drive shaft to which the vanes are coupled.
U.S. Pat. No. 5,199,864 to Stecklein discloses a rotary fluid pump that employs vanes rotating within a spherical housing and includes an interior carrier ring that guides a particular motion of the vanes so that they open and close to draw in and either pump or compress fluids. This patent also describes an embodiment (the “second embodiment”) that uses an exterior carrier ring to guide the reciprocal motion of the vanes. These devices are highly efficient, and are capable of displacing large quantities of fluid. In this type of pump the flow of fluid is typically controlled by the rate at which the rotary vanes are rotated. By increasing the speed, more fluid is pumped through the device, while decreasing the speed decreases the amount of fluid pumped. Further, reversing the flow through the device, if possible at all, requires the vanes to be rotated in the opposite direction or requires that the inlet and outlet ports be reconfigured or reversed.
U.S. Pat. No. 6,241,493 to Turner discloses a particularly useful improvement on this type of spherical fluid machine that is configured to enable adjustments in both fluid capacity and fluid direction without changing the speed or direction of rotation of the vanes in the device by adjusting the orientation of an interior carrier ring. That patent is incorporated by reference into this application.
Fluid machines such as that described in U.S. Pat. Nos. 6,241,493 and 5,199,864 have great potential in a number of applications because of their great efficiency compared to many rotary vane pumps. Other advantages are that they are already ported, meaning that the manner in which the chambers communicate with the inlet and outlet ports negates the need for valves. These fluid machines can operate efficiently as liquid hydraulic pumps, gas compressors, vacuum pumps, or reversibly as motors when a pressurized fluid is available as a motive force.
When used in gas compressor applications a number of issues arise due to the nature of this type of fluid machine. It is well known that the compression of gases raises the gas temperature and therefore adds heat to the pump internals. This is particularly important in this type of spherical design in which the moving vanes are encircling a central sphere in which heat can build up. Therefore means are needed for removing heat from the central sphere in these applications.
The prior art fluid machines as described in U.S. Pat. No. 6,241,493 can be especially long running from a maintenance perspective because there is no direct physical contact between either the vanes and the central sphere around which they rotate nor physical contact between the vanes and the exterior housing of the machine. Low leakage between chambers is maintained by maintaining small clearances that minimize slippage or fluid loss across the clearances. This non-contact design though can lead to some vibration issues, particularly at high rotation speeds so a new design approach is needed to provide a more robust structure to the internal rotating vanes and spherical internal ball.
Also when this type of fluid machine is used in a compressor mode the port size is purposely made small to ensure good compression performance. When the same fluid machine is needed to pump relatively incompressible fluids a larger port size or different port shape is needed to ensure that there is communication between the outlet port and the compression chamber during the entire compression cycle to avoid fluid locking of the pump.
Also, previous versions of this type of fluid machine flowed only one fluid through its interior. Similarly, compressors of this type of fluid machine flowed provided only one compression ratio at any given time of operation. To flow a second fluid or provide a second compression ratio, a second fluid machine was required, which disadvantageously adds equipment and maintenance costs and requires additional equipment space.
Also, previous versions of this type of fluid machine flowed only a single stream of fluid or two streams of fluid with only equivalent flow rates, or were used only singly as either a pump or a motor at any given time. To flow a second stream at a different flow rate, or to simultaneously operate a pump and a motor, a second fluid machine was required, with the same disadvantages mentioned above.
Previous versions of this type of fluid machine also provided an inadequate balance of forces on one or more of the vanes, contributing to unnecessary wear on moving parts in the machine.
What is therefore needed is a design that addresses these limitations in the prior art fluid machines, removing the heat of compression when they are operated as a compressor, increasing the robustness of the rotating structure, providing for the flow of multiple fluids through a single machine, providing for dual use of a single machine as both a pump and a motor, providing for simultaneous multiple compression ratios, providing for balanced forces across vanes, providing adequate adjustability in port size and/or port shape to facilitate operation as both a pump and a compressor for both compressible and relatively incompressible fluids, and providing for the flow of multiple streams of fluid at different flow rates.